Structural and electrical properties of amorphous GaAs sputtered at high substrate temperature (220 and 400 °C)

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• 作者：Benachir El Hadadi ; Hervé ; Carchano ; Jean-Luc Seguin and Hassan Tijani
• 关键词：Amorphous gallium arsenide ; Structure ; Thermalisation ; Conductivity ; Sputtering
• 刊名：Vacuum
• 出版年：2005
• 期刊代码：83_0042207x
• 类别：ph
• 出版时间：2005
• 卷：80
• 期：4
• 页码：272-283
• 文件大小：266 K

摘要

The influence of deposition conditions on structural and electrical properties of amorphous gallium arsenide (a-GaAs) thin films, deposited by RF sputtering at two substrate temperatures b=MathURL&_method=retrieve&_udi=B6TW4-4GMJ8YX-1&_mathId=mml33&_user=10&_cdi=5552&_rdoc=3&_handle=V-WA-A-W-AZ-MsSAYVA-UUW-U-AABZWDBWCC-AABBYCVUCC-CADVAWDUE-AZ-U&_acct=C000050221&_version=1&_userid=10&md5=7d6b76e9ebedeb9321e366e98a6392f6">bVlb-zSkWW" alt="Click to view the MathML source" align="absbottom" border="0" height=15 width=86> (glass substrates) and b=MathURL&_method=retrieve&_udi=B6TW4-4GMJ8YX-1&_mathId=mml34&_user=10&_cdi=5552&_rdoc=3&_handle=V-WA-A-W-AZ-MsSAYVA-UUW-U-AABZWDBWCC-AABBYCVUCC-CADVAWDUE-AZ-U&_acct=C000050221&_version=1&_userid=10&md5=37709de7777f85de374435f98db46d7f">bVlb-zSkWW" alt="Click to view the MathML source" align="absbottom" border="0" height=15 width=86> (Mo and ITO/glass substrates), is studied by both X-ray diffraction and electrical dark conductivity σ measurements, in the range (−150 °C to +150 °C) of temperature.

The increase of sputtering argon pressure, Pb>Arb>, leads to the growth of an amorphous structure and reduces the room-temperature dark conductivity, σb>RTb>, which suggests a reduction in the density of defects. Similar results are obtained with a decrease of the dc self-bias voltage, Vb>pb>, of RF electrodes. These results suggest that the density of defects is reduced with the energy decrease of the bombarding species while increasing Pb>Arb> or decreasing Vb>pb>. The product of the target-to-substrate distance by the argon pressure, (d×Pb>Arb>), representing the number of particles free path, confirms some results of the literature which indicate that the density of defects can be reduced significantly by reducing the energy of the bombarding species while increasing Pb>Arb> or decreasing Vb>pb>. Materials of great resistivity (≈10⁸ Ω cm) are obtained either for low Vb>pb> or for great d×Pb>Arb>. In addition, the thermal annealing reduces considerably the room-temperature dark conductivity.